Figure 3

Gene expression following short-term uni- and biaxial mechanical stimulation. Relative expression of chondrogenic (ACAN, COL2A1), de-differentiation (COL1A1), and superficial chondrocyte (PRG4) marker genes following dynamic (a–d) uni- or (e) biaxial stimulation for 1 hour at 1 Hz after (a) 7 or (c–e) 14 days of free swelling preculture. (a + b) Cell-laden GelMA-HAMA constructs were compressed at 10%, 30%, or 50% strain. (c) To investigate temporal changes in gene expression, constructs were compressed at 10% and samples taken for total RNA isolation 0 h, 2 h, or 4 h after compression. (d) Constructs were stimulated at 0.5 mm, 1.0 mm, or 1.5 mm sliding shear amplitude. (e) Constructs were stimulated with 30% compressive strain and either 0.5 mm, 1.0 mm, or 1.5 mm sliding shear amplitude. In all panels, gene expression levels of loaded constructs (L) were normalized to free-swelling controls (FS) cultured for the same duration (mean of free swelling controls indicated by broken line). Stars indicate a statistical difference between loaded and free swelling constructs (*p < 0.05, **p < 0.01, ***p < 0.001), while hashtags indicate statistical differences between loading regimes (#p < 0.05) (n = 4–6, one donor per study).